1 | /* |
2 | * Copyright (c) 2011 Broadcom Corporation |
3 | * |
4 | * Permission to use, copy, modify, and/or distribute this software for any |
5 | * purpose with or without fee is hereby granted, provided that the above |
6 | * copyright notice and this permission notice appear in all copies. |
7 | * |
8 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
9 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
10 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
11 | * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
12 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION |
13 | * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
14 | * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
15 | */ |
16 | #ifndef __CORDIC_H_ |
17 | #define __CORDIC_H_ |
18 | |
19 | #include <linux/types.h> |
20 | |
21 | #define CORDIC_ANGLE_GEN 39797 |
22 | #define CORDIC_PRECISION_SHIFT 16 |
23 | #define CORDIC_NUM_ITER (CORDIC_PRECISION_SHIFT + 2) |
24 | |
25 | #define CORDIC_FIXED(X) ((s32)((X) << CORDIC_PRECISION_SHIFT)) |
26 | #define CORDIC_FLOAT(X) (((X) >= 0) \ |
27 | ? ((((X) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1) \ |
28 | : -((((-(X)) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1)) |
29 | |
30 | /** |
31 | * struct cordic_iq - i/q coordinate. |
32 | * |
33 | * @i: real part of coordinate (in phase). |
34 | * @q: imaginary part of coordinate (quadrature). |
35 | */ |
36 | struct cordic_iq { |
37 | s32 i; |
38 | s32 q; |
39 | }; |
40 | |
41 | /** |
42 | * cordic_calc_iq() - calculates the i/q coordinate for given angle. |
43 | * |
44 | * @theta: angle in degrees for which i/q coordinate is to be calculated. |
45 | * @coord: function output parameter holding the i/q coordinate. |
46 | * |
47 | * The function calculates the i/q coordinate for a given angle using the |
48 | * CORDIC algorithm. The coordinate consists of a real (i) and an |
49 | * imaginary (q) part. The real part is essentially the cosine of the |
50 | * angle and the imaginary part is the sine of the angle. The returned |
51 | * values are scaled by 2^16 for precision. The range for theta is |
52 | * for -180 degrees to +180 degrees. Passed values outside this range are |
53 | * converted before doing the actual calculation. |
54 | */ |
55 | struct cordic_iq cordic_calc_iq(s32 theta); |
56 | |
57 | #endif /* __CORDIC_H_ */ |
58 | |